Single printing element typewriter



Aug. 7, 1956 J. E. HICKERSON SINGLE PRINTING ELEMENT TYPEWRITER 8 SheetsSheet 1 Filed Jazi. 19. 1955 INVENTQR OHN E.Hl KERSON :Qfi 0 r ATTO NEY 7, 1956 J. E. HICKERSON,

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ABC/\TA Aug. 7, 1956 J. .E. HICKERSQN SINGLE PRINTING ELEMENT TYPEWRITEZR 8 Sheets-Sheet 3 Filed Jan. 19, 1953 VE TOR 44 IN N OHN E.Hl RSON 1/ K/Mmv; ATTORNEY 7, 1956 J. E. HICKERSON 2,757,775

SINGLE PRINTING ELEMENT TYPEWRITER Filed Jan. 19, 1953 8 Sheets-Sheet 4 Aug. 7, 1956 J. E. HICKERSON SINGLE PRINTING ELEMENT TYPEWRITER 8 Sheets-Sheet 5 Filed Jan. 19, 1955 INVENTOR HN Ev HlC ERSON ATTORNEY 7, 1956 J. E. HICKERSON 2,757,775

SINGLE PRINTING ELEMENT TYPEWRITER Filed Jan. 19, 1953- 8 Sheets-Sheet 6 1 10 1k: Ull

l/ 2 INVENTOR .x\ HN E.HIOKERSON |=|s.11 1 7 ATTORNEY Aug. 7, 1956 J. E. HICKERS ON SINGLE PRINTING ELEMENT TYPE-WRITER Filed Jan. 19, 1953 8 Sheets-Sheet 7 mad;

INVENTOR HN EHI ERSO ATTORNEY Aug. 7,. 195 I J. E. HICKERSON SINGLE PRINTING ELEMENT TYPEWRITER 8 Sheets-Sheet 8 Filed Jan. 19, 1953 o NumcO INVENTOR JOHN E.H|C ERSON ATTORNEY United States Patent SINGLE PRINTING ELEMENT TYPEWRITER John E. Hickerson, Wappingers Falls, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application January 19, 1956, Serial No. 332,045

12 Claims. (Cl. 197-49) This invention relates to typewriters, and more particularly, to an improved typewriter construction and operation which is particularly suitable to portable typewriter use.

For many years, typewriters have had a somewhat conventional construction comprising a plurality of type bars operable respectively, by individual key bars, a carriage movable laterally to present a new space to a single print position, an inking ribbon, and means for holding the parts in operable arrangement. The important point is that each type bar-in response to operation of its assigned key barstrikes the single print position of the machine while the carriage is movable laterally to present new spaces step by step into alignment with the single print position. The conventional construction involves considerable expense in maintaining the close tolerances required for the plurality of type bars to strike the identical print position. Accordingly, it is an object of this invention to reduce typewriter cost by providing an improved typewriter having a single type head which is operable in response to each of the key bars to position a selected character in a chosen print position.

It is a further object of this invention to provide an improved typewriter having a stationary paper holding element which takes the place of the conventional, laterally moving carriage.

In a usual typewriter construction, considerable expense would be involved in changing the type characters usedfor example, from roman to italic or gothic. In accordance with this invention, however, it is a still further object to provide an improved typewriter wherein the type characters may be readily interchanged.

It is a further object of this invention to provide a standard keyboard typewriter having a considerably reduced size and number of operating parts.

It is a further object to provide an improved character selecting mechanism in the form of a wire and pulley arrangement through which there is obtained positive alignment of the selected character.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

Briefly, this invention relates to an improved typewriter having a prism shaped type head, wherein all the required type characters are arranged on its faces in column by column and side by side or row alignment. The type head is moved transversely of the machine in coordination with a print hammer which can strike against one of the type characters at a time. The print hammer and the type head are moved across a page in response to vertical displacement of individual key bars to present one character at a time to laterally stepped print positions.

In the drawings:

Fig. 1 is a perspective view of the improved typewriter.

Fig. 2 is a perspective view of one embodiment of a type head rotated away from a home position.

Fig. 3 is a laid out view of the faces of the type head shown in Fig. 2.

Fig. 4 is a plan view indicating the relative positions of a type head and a print hammer.

Fig. 5 is a vertical section at plane 55 of Fig. 4 in the direction of the arrows.

Fig. 6 is a perspective view schematically indicating the structure utilized for advancing the type head laterally.

Fig. 7 is a perspective view schematically indicating the structure used for rotating the type head.

Fig. 8 is a perspective view schematically indicating the structure utilized for tripping a print hammer and for moving it in conjunction with the movement of the type head.

Fig. 9 is a perspective view explodedto show an interchangeable type head.

Fig. 10 is a plan view showing the assembly of the basic elements schematically shown in Figs. 6, 7 and 8.

Fig. 11 is a sectional view of the interchangeable type head shown in Fig. 9.

Fig. 12 is a vertical section taken on the plane 1212 of Fig. 10 in the direction of the arrows.

Fig. 13 is a vertical section taken on the plane 13-13 of Fig. 10 in the direction of the arrows.

Fig. 14 is a schematic diagram showing the notching for the type character selecting elements of the typewriter.

Referring to the drawings and more particularly to Fig. 1, a typewriter 1 is shown comprising the usual keys 2 arranged on the standard keyboard, a base 3, and a new and different type head 4 with cooperable print hammer 5. Specifically, the type head is prism shaped having type characters arranged on its faces in column by column and side by side alignment. In the disclosed embodiment-note particularly Figs. 2, 3the type head is shown as a prism of octagonal cross-section. The type head in Fig. 2 has been rotated through 180 in order to give a better view of its functional faces. Print characters are arranged on only seven faces of the octagonal prism and each face has six charactersa total of forty-two characters. The characters on each face are in columnar alignment in that each character on any face is directly above or below a corresponding character on a contiguous face.

It should' be noted, however, that the type head in its disclosed form is not to be considered as a limitation on the scope of this invention, rather has it been selected merely as an example to illustrate more clearly the operating features and principles of this invention.

The type head 4 has a home position 6 (Fig. 3) which is that space defined by the intersection of one of the columns of characters and the central of the functional faces of the octagonal prism. The character C in the particular arrangement of characters shown in Fig. 3 is located at the home position 6. Definition of the home position of the type head is important since, unlike the conventional machine, which has but a single print position, the print position of the typewriter 1 is movable in suitably spaced steps across a page to be printed, while the page remains stationary. Only line by line motion need be imparted to the page to be typed. At the beginning of each print stroke, the home position 6 of the type head is in alignment with the selected print position of the typewriter.

. The broad theory of the printing technique of this improved typewriter is shown in Figs. 4 and 5 wherein a sheet or page of paper 7 is positioned between the type head 4 and the print hammer 5 with a suitable carbon element 8 being positioned between the paper and the type head. The print hammer 5 has a striking face equal in width to that of any one type character whereby one character at a time is imprinted on the page each time the hammer 5 is driven against the type head 4. In order to print a line of type, character by character, the print hammer 5 and the home position 6 of the type head are moved simultaneously to stepped print positions across the page 7.

The print hammer 5 is operable through a structure hereinafter described to strike the type head 4 in each selected print position of the typewriter. It has been mentioned in the preceding paragraph, however, that the home position 6 of the type head moves simultaneously with the print hammer to each new print position. It follows, therefore, that unless the type head is movable relative to the print hammer, a series of C"s (the home position character) would be printed each time the print hammer was operated. A selecting means for moving the type head relative to its home positiona movement necessary for normal printing-whereby a selected character is presented to the print position, is shown in Figs. 6 and 7. Specifically, Fig. 6 shows the mechanism for moving the type head 4 axiallyi. e. across the page both to stepped print positions and also column by column relative to the print position, while in Fig. 7 a mechanism is shown for rotating the type head to present a selected one of its faces to the print position.

Referring to Figure 6, the type head 4 is shown mounted in a bracket 9 which in turn is supported for axial movement on a shaft 10 for a purpose to be hereinafter described. Bracket 9 has integrally therewith a suitable anchor block 11 to which there is removably attached the opposite ends of a tape or ribbon 12. The type head, through structure hereinafter described, is movable along the shaft 10 in response to movement of ribbon 12 both to present the type head home position 6 to successively stepped print positions and to move the type head along shaft 10 relative to the selected print position. This dual function of ribbon 12 is brought about by a pulley system including the pulleys 13, 14 and 15 which lead one section of tape 12 from a terminal point 16 on block 11 to a certain base plane located below the type head. A similar set of pulleys 17, 18 and 19 conduct another section of the tape 12 from a terminal point 20 on block 11 to the base plane. The tape 12 then travels a serpentine path in the base plane from pulley 15 to pulley 19; that is, the tape 12 is lead from pulley 15 about a pair of laterally (relative to the typewriter base) movable pulleys 21 and 22, about a fixed or guide pulley 23 to a drive pulley 24, and clockwise about the latter to some anchor point (see Fig. 10) where the tape 12 is secured to drive pulley 24. From anchor point 25, the tape continues clockwise about drive pulley 24, about guide or fixed pulley 26, and a pair of laterally movable pulleys 27, 28 to pulley 19.

Tape 12, which is not rigid, cannot push the type head across the page. Accordingly, in the disclosed embodiment, in order to effect an axial movement of the type head in response to tape movement, the tape 12 is employed as a constant length belt. That is, the pulley structure above described is arranged so that any change in the clockwise tape distance between drive pulley 24 and any one print position is simultaneously followed by a corresponding complementary change in the counterclockwise tape distance between drive pulley 24 and the same print position. It follows therefore, that type head 4 (in effect a part of the tape) will move in response to any axial movement of the tape 12.

With the pulley and tape arrangement described, the drive pulley 24 can move the type head across the machine between the pulleys 13 and 17. The movable pulleys 21, 22 and 27, 28, however, act as a lateral selecting means and are positioned to superimpose a movement on the tape in addition to that caused by the movement of the drive pulley 24. Specifically, counterclockwise rotation of drive pulley 24 permits the home position 6 of the type head to be moved successively to stepped print posi tions of which one is A (Fig. 6). At this instant, a point B on the tape will be a fixed distance from the print position A. Then, with drive pulley 24 stationary, any displacement of the movable pulley 21 towards the fixed pulley 15 will decrease the clockwise tape distance between drive pulley 24 and the print position A, fllereby permitting the point B on the tape to move to a new point 1:. Accordingly, the home position 6 of the type head 4, which normally is aligned with the print position A, can move to the right a distance equal to the distance between B-b on the tape for presenting a column of type head 4, other than the central or home one, to the print position A.

Since the movement of the type head in response to movement of tape 12 is based on the tape being of constant length, it follows that any displacement of movable pulley 21 relative to fixed pulley 15 must be followed simultaneously by an equal displacement of one of the movable pulleys 27, 28 (or a combined equal movement) relative to fixed pulley 15. A simple means for assuring corresponding movement of the pulleys 21 and 28 is to position them a fixed distance apart on a bar movable laterally of the typewriter--in this case a certain permutation bar 29. The second pair of movable pulleys 22 and 27 which must function similarly to the pulleys 21 and 28 are fixedly positioned on a second displaceable permutation bar 30. With this structure, any movement of the movable pulley 21 toward the fixed pulley 15 will be followed by a simultaneous corresponding movement of the movable pulley 28 toward the fixed pulley 15. Similarly, any lateral movement (relative to the type writer base) of either one of the movable pulleys 22 or 27 will be followed by a simultaneous equal movement of the other pulley.

The permutation bars 29 and 30, as indicated in Fig. 6, are notched at 31 to provide cam surfaces 32 which function in combination with a vertically moving key bar 33 to displace the permutation bars laterally of the typewriter. Actually the key bars-see bar 33. Fig. 6--are positioned transversely of the longitudinal axis of the permutation bars 29, 30 whereupon, when the lower edge 34 of a key bar strikes a permutation bar cam surface 32, the permutation bar moves to the right or left depending on the slope of the cam surface 32.

More specifically, the generally triangular notches, in addition to providing the sloping cam surfaces 32, include an additional vertical notch or slot 35 of a width equal to that of its cooperating key bar. Notch 35 is located at the bottom of the notch 31 and permits a vertical movement of its cooperating key bar in addition to that vertical movement that takes place while the key bar is in engagement with the cam surface 32. The shape of the notches 31, therefore, permits each key bar to actuate the permutation bars 29, 30 and then to release the print hammer, as hereinafter described, while the permutation bars are held stationary in their displaced positions.

Movement of the permutation bars naturally results in a displacement of the movable pulleys and a consequential movement of the type head 4 relative to any one print position. Accordingly, the cam surfaces 32 are designed to have slopes that effect an axial movement of the type head 4 in steps equal to the type column width of the characters on the faces of the type head 4.

Since in the disclosed embodiment, there are forty-two characters arranged in six columns, it is obvious that the required movement of the type head, in order to present any column of type characters to the print position, is two columns to the right and three columns to the left at home position 6.

Accordingly, the permutation bars 29 and 30 are designed so that a number of cam surface combinations are actuated to move the type head; that is, depression of the D key bar (see Figs. 3 and 14), for example, might move permutation bar 29 one unit of space to the left thereby causing movable pulleys 21 and 28 to be displaced one unit of space to the left and cause the type head home position 6 to move one unit of space to the right of the immediate print position whereupon the column immediately to the left of the home column will be presented to the print position. The depression of the 4 key bar, on the other hand (see Figs. 3 and 14) might cause permutation bar 29 to move one unit of space to the left and permutation bar 30 to move two units of space to the right. Accordingly, movable pulleys 21 and 28 would move one unit of space to the left while movable pulleys 22 and 27 would move two units of space to the right, and the home position of the type head 4 would move three columns to the right to present the left end column of the type head to the print position.

In the previous description, it has been specified that the type head 4, in addition to being axially movable from one to three column widths in either directionmust be rotatable from a home face (see Fig. 2) to any one of three octagonal prism faces clockwise and any one of three faces counterclockwise in order to present all the type characters to a print position.

To accomplish the required rotation, type head 4 is key or spline mounted on shaft to provide for axial movement of the type head along the shaft while effecting rotation of the type head in response to rotation of the shaft. Specifically, shaft 10 is provided with an elongated keyway 36 (see Figs. 5 and 11) which has a cross sectional dimension that closely approximates that of a spline'or key 37 in a base 38 of type head 4, thus establishing an axially sliding fit between the type head and shaft. The type head 4 is mounted for rotation relative to bracket 9 by means of suitable bearings 39 (Fig. 6). The bracket 9, in turn, is connected to tape 12 through block 11 as described above. This structure permits axial movement of the type head relative to shaft 10 in response to movement of tape 12; and also permits simultaneous rotational movement of the type head with corresponding rotation of the shaft 10.

The rotational movement of shaft 10 is brought about by a gear 40 (see Fig. 7) fixed to one end of shaft 10 and enmeshed with a drive gear 41. A pulley 42 shaped to accommodate a tape or ribbon 43 is fixed integrally to gear 41 to drive the same in response to axial tape movement.

The tape 43 is similar to tape 12 and, by means of fixed pulleys 44 and 45, one section of it is conducted from pulley 42 to the base plane described with respect to Fig. 6. Another section of tape 43 is conducted by means of pulleys 46, 47 and 48 to the base plane. Between pulleys 48 and 45, the tape is brought aboutmovable pulleys 49, 50, 51 and 52. Movable pulleys 50 and 51a part of a rotational selecting meansare positioned a fixed distance apart on a permutation bar 53. The tape 43 necessarily I is anchored to the typewriter body at a point 55 to effect rotation of pulley 42 and gear 41 in response to lateral (relative to typewriter base) displacement of permutation bars 53, 54.

With this construction, any displacements of pulleys 49 and 52, for example to the left, will cause a decrease in the clockwise tape distance between anchor point 55 and pulley 42; and a corresponding increase in the counterclockwise tape distance between anchor point 55 and pulley 42. Accordingly, with a constant tape length some point C on tape 43 would be moved downwardly to a new point c, and pulley 42, as viewed in Fig. 7, would be rotated clockwise a peripheral distance equal to Cc. Such a movement is arranged to present a new octagonal face of type head 4 to the print position.

The permutation bars 53 and 54 are notched similarly to the permutation bars 29 and 3!) to present suitable sloping cam surfaces 56 which are operable in conjunction with the same key barse. g. key bar 33-that actuate the permutation bars 29, 30, thereby to effect an axial movement of the permutation bars 53, 54, and the consequential transverse movement (relative to the typewriter base) of the movable pulleys 49, 52 and 50, 51. The cam surfaces have such a slope that the combined efiect of the resultant permutation bar movement and the gear ratio between gears 41, 40 efiects a maximum of three octagonal faces of rotation of type head 4 clockwise and counter-clockwise from the home face. Permutation bars 53, 54 also have slots 57, similar to slots 35 to accommodate the key bars for their control function; i. e. actuating the trip hammer, etc.

It is to be understood, therefore, that with the structure presented in Figs. 6 and 7, the depression of any key bar can simultaneously actuate permutation bars 29, 30, 53 and 54 to effect both an axial and rotational movement of type head 4 thereby to present a selected character to a print position.

The permutation bars 29, 30, 53 and 54 are each spring loaded with respect to their axial displacement; that is, springs 58 (Figs. 6 and 10) are positioned at opposite ends of each of the permutation bars. The function of the springs 5-8 is to restore the permutation bars to their normal or home position (shown in Fig. 10) after a key bar is raised out of engagement with their respective cam surfaces. Since the displacement of the permutation bars effects movement of type head 4 relative to any print position, it is apparent that after each imprinting of a character, the type head 4 will be restored to its home position, in response to restoration of the permutation bars to their normal or home position.

In the previous discussion, it has been explained that type head 4 is to be moved across a page to successive print positions, and that it is to be moved from a home position to present a selected character to a print position. It has also been explained that a print hammer 5 which is moved to successive print positions, corresponding to those of the type head, is positioned behind a sheet of paper 7 where it can strike the paper against the type head to effect the imprinting of the selected character on the paper. It is reasonable, therefore, that both the print hammer and the home position of the type head should be moved simultaneously to successive new print positions. Since drive pulley 24 controls the lateral movement of the home position of the type head 4, it follows that a simple method for laterally moving the print hammer in conjunction with the home position of the type head is to axially connect to drive pulley 24 a second drive pulley 59 of equal diameter. Then, by connecting the print hammer 5 through a suitable tape system to drive pulley 59, the print hammer 5 and type head 4 will move simultaneously in response to movement of pulleys 24 and 59.

In Fig. 8, the pulley 59 is shown accommodating a tape 60 that is connected to a hammer body 61 which slidably supports print hammer 5 in suitable guides. Specifically, tape 60 which is anchored to drive pulley 59 at some point 62, is brought clockwise about pulley 59 from the anchor point 62 to a guide pulley 63, then about a pulley 64 which changes the direction of the tape 60, and about a second pulley 65 which again changes the direction of the tape 60 and brings it to a plane which includes the hammer body 61. One end of the tape 60 is secured to a terminal point 66 (Fig. 10) on the hammer body 61, while the opposite end of the tape 60 is secured to a corresponding point 67 (Fig. 10) on the body 61. The tape continues from the point 67 about pulleys 68, 69, 70, then crosses under its other section at 72 and engages pulley 59 at a point 73. It is to be understood that the tape 60 meets the pulley 59 tangentially at the point 73, and continues clockwise around the greater are of the pulley past anchor point 62 to a second point 74, where tape 60 tangentially leaves the pulley 59. Since the print hammer 5 is to move across an entire page, the length of the great arc of drive pulley 59 from the points 73 tov74 must be equal at least to the required movement of the print hammer 5. Pulleys 75 and 75a are provided 7 merely to guide tape 60 onto drive pulley 59, and hammer body 61 is slidably mounted on a suitable shaft 76 for movement across the machine in response to axial movement of tape 60.

Since, for legible printing, the printed characters should be uniformly spaced apart, and since the type head and the print hammer are to be moved simultaneously, an escapement or ratchet means (shown generally in Figs. 6 and is provided to move the print hammer 5 and type head 4 across a page to suitably spaced printing positions.

In one embodiment, the escapement means comprises a ratchet mechanism 77 and a cooperable ratchet wheel 78 which, in turn, is integral with and in axial alignment with the drive pulleys 24 and 59. Operation of the escapement means, i. c. the interaction of the ratchet mechanism 77 with ratchet wheel 78, will effect an axial movement of the tapes 12 and 60 to produce equal movements of the type head 4 and the print hammer body 61. The teeth on the ratchet wheel 78 are arranged to move the type head 4 and hammer body 61 across a page in equal steps.

In one embodiment, the ratchet mechanism 77 comprises a dog 81 and a pawl 82; and an operating mechanism actuates the ratchet mechanism 77 so that the dog 81 and pawl 82 engage successively with the teeth of wheel 78. The dog 81 is arranged for both pivotal and slight longitudinal movements on a shaft 84 extending perpendicularly from the base of the typewriter. A shoulder 83 is positioned on an extension of dog 81 remotely from both the pivot point 84 and from wheel 78. A spring 85 pulls on the extension to force the dog 81 both longitudinally and angularly into engagement with the teeth of wheel 78, and thereby prevent counterclockwise rotation of the wheel 78. The ratchet operating mechanism includes a rocker arm 86 supported by and rotatable with a transverse shaft 87 for engagement with the shoulder 83 on the dog 81. Fixed to the shaft 87 is a bail 88 which is operable to rotate the shaft about its axis so as to actuate the dog 81 through the rocker arm 86. The bail 88 is positioned transversely across the typewriter to be actuated by any key bar cooperating with the permutation bar notches 35 and 57. The key depresses the bail 88 for effecting a release of the dog 81 from wheel 78.

Since it is desired that the wheel 78 move in steps to effect a suitable spacing for a uniform and legible printing, it is necessary that the escapement mechanism effect a uniform stepped counterclockwise rotation of the wheel 78. The escapement mechanism therefore, includes the pawl 82 which is positioned for angular movement about a vertical shaft 90 and which is biased by spring 91 normally out of engagement with the wheel 78. However, movement of the dog 81 in opposition to the spring 85 causes a set screw 92 on dog 81 to push against a shoulder 93 on the pawl 82 to engage the latter with a tooth on wheel 78 and prevent its rotation in a counterclockwise direction when the dog 81 is released from engagement with its tooth. With the dog 81 released, the spring 85 moves it longitudinally to a position for engagement with the next tooth on the wheel.

The subsequent release of the key bar permits the spring 85 to rotate the arm 86 with shaft 87 and raise the bail 88 to its normal position. This action further causes the dog 81 to pivot about the shaft 84 and disengage the holding pawl so that the ratchet wheel turns until the next tooth engages the dog 81, thereby effecting the escapement of the ratchet wheel for moving the type head 4 to a new printing position. The structure of the dog and escapement mechanism is a common one which permits wheel 78 to rotate counterclockwise past the dog 81 one tooth at a time.

In order that the wheel 78 may rotate when released, a continuous torque is applied to the wheel tending to rotate it in opposition to the stop action of dog 81 and pawl 82. In one embodiment, this torque is supplied by a scroll-type coil spring 94 (see Fig. 10) which is positioned beneath and connected at one end to wheel 78 while its other end is connected to the base of the typewriter.

The print hammer 5 not only has to be moved to successive print positions, but it also must be triggered at each print position to effect the imprinting of a character on a page. In Figs. 4 and 8, the print hammer 5 is shown slidably mounted in suitable guides 95, 96 (Fig. 4) positioned on the hammer body 61. A spring 97 is positioned on body 61 and in engagement with the hammer 5 tending to force it outwardly away from the body 61 and towards type head 4, an action required for each print stroke. In order for the print hammer to function without smearing the print, it is necessary that the hammer be withdrawn from the type head after each print stroke. Accordingly, the print hammer should be triggered from a cocked position and driven under the influence of spring 97 into engagement with type head 4, and immediately after the print stroke, the hammer 5 should be re-cocked.

The required hammer operation is brought about (see Fig. 8) by a tape 98 which is secured at one end to a stationary block 99. The tape is conducted around a pulley 100 on the hammer body 61. about a pulley 101 positioned on the print hammer 5, about a pulley 102 on the body 61, about a pulley 103 which changes the direction of the tape 98, about a pulley 104 which is movable to place tension on the tape in a manner hereinafter to be described, and about a pulley 105 to a stationary anchor block 106. The pulley 104 is rotatably mounted on an arm or hell crank 107 which is normally held in a latched position shown in Fig. 8, and the print hammer 5 is held by the tape 98 at this time in its retracted or cocked position against the action of the spring 97. The release of the bell crank 107 releases the tension on tape 98 and permits the spring 97 to drive the print hammer 5 towards the type head 4.

The pivotal movement of the bell crank 107 is controlled by a solenoid 108 in conjunction with the release of a latch 109. Specifically, with the arrangement of the elements shown in Fig. 8, an axial pull on a rod 110 towards the front of the typewriter rotates the latch 109 about its pivot point 111 to release the bell crank 107 which carries pulley 104. Assuming there is no power on the solenoid 108 at this instant, the pulley 104, under the influence of spring 97, will move upwardlywith the bell crank 107 rotating about its pivot point 111.

In the disclosed embodiment. solenoid 108 is connected through a pair of normally open contacts 112 to a source of power, such as a battery 170, and is connected by a conductor 171 to the other side of the battcry. For controlling the contacts 112, there is provided a lever 115 pivotally mounted at 116 and connected to a spring arm 117 carrying one of the contacts 112. Upon rotation of the lever 115 in a counterclockwise direction in Fig. 8, the spring arm 117 is moved so as to engage its contact 112 with the other contact which is carried by an arm 118. Extending beneath the outer end of the lever 115 is a bar 113 which is urged upwardly against the lower surface of the lever by a spring 172. The forward end of the bar 113 is connected, as shown in Fig. 12, by a link 119 to a crank 1.20 on the shaft 87. Upon depressing any one of the key bars 33, the bail 88 is actuated to rotate the shaft 87 and effect forward movement of the bar 113. The arrangement of the bar 113 is such that its rear end moves out of contact with the lever 115 just before the key lever is depressed to its lowermost position.

It is desired that the latch 109 be disengaged from the bellcrank 107 just after the bar 113 is moved out of contact with the lever 115.

A depression of any one of the key bars 33 first causes the permutation bars 29, 30, 53 and 54 to be moved longitudinally by engagement of the key bar with the cam surfaces 32 and 56. This effects a posi tioning of the type head 4 relative to the hammer 5 so that the character corresponding to the key bar is presented for engagement by the hammer. The bail 88 is actuated during this time to rotate the shaft 87 so as to move the bar 113 forwardly. After the key bar reaches the lower edges of the cam surfaces on the permutation bars and starts moving into the vertical notches 35 and 57, the bar 113 moves from under the lever 115. A slight additional depression of the key bar causes the latch 109 to be disengaged from the bellcrank 18! so that the hammer is actuated by the spring 97 to engage the type head.

It will be appreciated that the bar 113 is lifted by the spring 172 as soon as the bellcrank 107 is raised, and the lifting of the bar is limited by an abutment (not shown) so that the end of the bar engages the lever 115 upon rearward movement.

The rocking of the bail 88 by the key bar also causes the arm 86 on the shaft 87 to disengage the dog 81 from the toothed wheel 78 and to engage the pawl 82 with the wheel for holding the latter against rotation. As soon as the dog 81 is disengaged from the wheel, the spring 85 moves the dog a slight distance longitudinally so that its nose is in a position to be engaged by the next tooth on the wheel.

Upon releasing the key bar, the bail 88 is rocked upwardly by the action of the spring actuated dog 81 on the arm 86. The key bar 33 is lifted by the bail and the shaft 87 rocks at the same time to move the bar 113 rearwardly. Just before the key bar moves out of the vertical notches 35 and 57, the bar 113 rocks the lever 115 to close the contacts 112 for energizing the solenoid 108 and retracting the hammer to its cocked position. As the bar 113 moves rearwardly, the rod 110 moves with it until an inclined cam surface 122 on the head of the latch 109 engages the bellcrank 187 in its upper position. Upon energizing the solenoid the bellcrank moves downwardly and cams the latch 109 forwardly until the bellcrank reaches a position at which the latch moves over it under the action of the spring 121. As the bellcrank moves downwardly, it engages the bar 113 and forces thev latter to a position below the lever 115 so that the contacts 112 open again under the action of the spring arm 117.

When the key bar moves upwardly out of the vertical notches 35 and 57, the permutation bars are recentered by the action of the springs 58. This causes the type head to be returned to its home position, and, since the hammer has already been retracted, there is no engagement between the paper and the type head to cause a smearing action. The upward rocking of the bail 88 also causes the pawl 82 to be disengaged from the toothed wheel 78 so that the latter turns in a counterclockwise direction in Fig. 6 until the dog 81 arrests its motion by engagement with the next tooth. The pulleys 24 and 59 rotate with the toothed wheel and actuate the pull tapes 12 and 60, respectively, to shift the type head and hammer to a new printing position.

Interchangeable typehead It has been pointed out that one of the objects of this invention was to provide an interchangeable type head 4. Such an interchangeable structure in one form is shown in Fig. 9, wherein shaft carries an axially slidable type head base 38 which in turn has a key like protrusion 124 which fits into a spline 125 in a concentric outer prismatic type element 126. The spline is located opposite the home face of the type element 107 (the bottom face as seen in Fig. 9). The prismatic type element 126 is secured to the concentric interfitting type head base 38 through the interengagement of a knurled nut 127 and a threaded portion 128 of the base. Specifically, one end of base 38 has a suitable stop, e. g. bearing 39, for limiting the axial motion in one direction of type element 126, and nut 127 holds the type element 126 against bearing 39. Bracket 9, meanwhile, is provided with bifurcated ends 129 which are engageable with suitable grooves 130, 131 located in bearing portion 39, and knurled nut 127, respectively. With this simple, yet unique structure, bracket 9 can be pulled away from shaft 10 after tape 12 has been disconnected (as shown in-Fig. 9), and nut 127 can be removed so that the prismatic type element 126 can be slid to the right for disengagement from type head base 38, and a replacement type element can be inserted in place of the removed one. It follows that any number of type elements can be utilized and interchanged at the will of the operator. It should be understood too, that this is only one embodiment of the removable type head. In another embodiment the bracket 9 might have only one, suitably braced, bifurcated leg whereupon the type element 126 could be removed without pulling bracket 9 away from the shaft 10.

Resetting the typehead In the discussion with respect to the movement of the type head and the print hammer across the page, details were set forth for controlling the movement of these elements from the left to right, but no structure was described for resetting the type head and the print hammer to the left hand margin. In the simplest functioning embodiment of this improved typewriter, the type head 4 and print hammer 5 can be reset to the left hand marginsimply by pushing them along their respective guide shafts 10 and 76. During this motion, the ratchet wheel 78 rotates past the ratchet mechanism 77, since the dog 81 and pawl 82 prevent only counterclockwise movement of the wheel. Incidentally, this rotation of the ratchet wheel causes the spring 94 to be rewound.

In Figs. 1, 10, and 13, however, a mechanical device is shown for restoring the type head and print hammer to the left hand margin. Specifically an arm 132 which is shown protruding from the front of the machine is employed to restore the type head and print hammer to the left hand margin after each line of print. The operation of the arm 132 is simple (see Fig. 13) in that a third drive pulley 133 equal in diameter to the pulleys 24 and 59 is axially secured to them. Drive pulley 133 accommodates a tape 134 which is secured to pulley 133 at an anchor point 135 (Fig. 10). Tape 134 is led by suitable guide pulleys 136, 137 from drive pulley 133 to the handle 132. The tape 134 is connected to terminal points 138, 139 on each side of handle 132 to move it to the right with, tape 134 as the type head moves across a page. In reverse movement, the handle 132 will move the tape 134 and restore the pulleys 133, 24 and 59 and consequently the type head and print hammer to the left hand margin of the machine.

Inking ribbon Another feature of this invention deals with the inking ribbon which is employed for the printing operation. While any conventional ribbon arrangement, such as those comminly used on typewriters would suffice for the operation of my improved typewriter, it has been found that it is more desirable to support the ribbon 8 (Fig. 5) between a feed reel 140 on one side of the machine and a winding reel 141 on the opposite side of the machine (Figs. 10, 12 and 13) with a length of the ribbon being supported. between these two reels in suitable guides (not shown) so that the ribbon lies between a page 7 and the typehead 4. The ribbon 8 remains stationary during the movement of the type head and print hammer from left to right across a complete line of type but, upon the resetting of the type head 4 and the print hammer 5 to the left hand margin, the ribbon will be wound on reel 141 and a new length of ribbon will be positioned between the reels 140, 141. To accomplish this result, the wind reel 141 is connected by means of shaft 142 to a one way clutch 143.

One way clutch 143 in turn is driven by belt 144 which in turn is driven by the ratchet wheel 78. Movement of the wheel 78 in a counterclockwise direction (Fig. 10), which permits the type head 4 and print hammer 5 to move across the page from left to right, will not rotate the wind reel 141, but the resetting of the type head 4 and the print hammer 5 changes the direction if rotation of the wheel 78 to clockwise and then one way clutch 143 is actuated to cause wind reel 141 to pull the tape across the machine, so that a new section of the ribbon is ready for the next line of print.

Spacing mechanism A spacing mechanism as shown in Figs. 10, 12 and 13 comprises a space bar 145, a bell crank 146 operable in response to vertical movement of the space bar, and a pusher rod 147 interconnected with the bell crank 146 to actuate the ratchet mechanism 77. Specifically, space bar 145 is secured for rotation with shaft 148 through extensions or arms 149. Shaft 148 in turn, is supported for rotation in brackets 150 and has aflixed thereto the bell crank 146. Pusher rod 147 is pivotally connected at point 151 to the crank arm 146 for movement towards and away from ratchet operating shoulder 83 on the dog 81. A spring 152 acts on bell crank 146 to maintain pusher rod 147 normally in its retracted position away from shoulder 83. With this structure, depression of space bar 145 rotates shaft 148 and bell crank 146 to effect a motion of pusher rod 147 rearwardly towards shoulder 83, which motion actuates the ratchet mechanism 77 in a manner hereinbefore described to advance the type head 4 and print hammer 5 across a page in spaced steps.

Paper guide In the early portions of this description, it was mentioned that the page 6, during a printing operation, is held between print hammer 5 and type head 4. While any convenient paper holding structure will suffice to hold a sheet of paper 7 in a print position, a disclosed form which is intended for illustrative purposes only is shown as a chute 153 (see Fig. 5) which is provided for guiding a page 7 to a suitable position between the type head 4 and print hammer 5. The chute 153 comprises a pair of guide sheets 154, 155 spaced apart in overlying relationship to guide a page 7 from the time of its insertion into the machine at a month 156 downwardly and through a bend 157, approximately 180 degrees, and into alignment with a pair of feed rollers 158, 159. Just short of the feed rollers, the guide sheets 154, 155 are terminated as by securing them to transverse support rods 160, 161 respectively. The feed rollers 158, 159 through a frictional drive, send the page 7 up into a print position between the type head 4 and print hammer 5. Obviously, a suitable ratchet mechanism (not shown) could be employed to control line spacing for the page 7 in the conventional single, double or triple line space steps. Attached to one of the feed rolls is a handle 170 (Fig. l) for rotating the rolls to position the page 7.

It should be understood that while many features can be added to this basic machine to increase its marketability-for example, tabulating mechanism and margin stops could be added-these features are available on standard machines and, since they do not contribute to this invention, there is no need to describe their application to my improved machine.

Of incidental interest is a structure that is provided for guiding the positioning of the type head to insure horizontal alignment of the printed characters. Specifically, as shown in Figs. 8 and 12, a starwheel 162 is provided having teeth equal in number to the faces of the type head. An actuating rod 163 is pivotally positioned by stud 164 for engagement with the teeth of the starwheel 162. That is, when actuating rod 163 is in engagement with a space between two teeth of the starwheel, the face of the type head corresponding to that inter-tooth space 12 will be properly aligned for uniform vertical positioning of the printed characters.

The purpose of the star wheel structure is to correct for any minor inaccuracies that might develop in the tape systems as a result of temperatures (e. g. tape expansion or shrinkage). A triggering lever 165 is pivotally supported on the typewriter base by a stud 166. The triggering lever 165 is positioned for operation in response to forward movement of the bar 113. In other words, when a key bar pulls bar 113 forward an ear 167 on bar 113 moves triggering lever 165 which in turn causes actuating rod 163 to align the star wheel 162 and type head 4. This aligning action takes place just before the latch 109 is released to effect an operation of the hammer.

Size

The improved typewriter construction described is particularly suitable to portable typewriters since it permits the manufacture of a standard key board typewriter having dimensions in the order of 8" x 10" x 3"-much smaller than conventional portable typewriters.

A machine built in accordance with the structure hereinbcfore described will have approximately half the number of parts found in one of the more simple of the nationally manufactured portable typewriters and considerably less parts than any other nationally manufactured portable typewriters. It follows, therefore, that this new typewriter construction permits the manufacture of a simpler and less expensive typewriter than has heretofore been known.

In Fig. 14 the permutation bars are shown schematically as having suitable cam surfaces for effecting the proper operation of the type head in response to depression of any key bar. A character is assigned to each key bar and the cam surfaces that it engages (if any) are shown on each permutation bar.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A typewriter comprising, in combination, a prismatic type head having a plurality of print characters arranged on its faces in column by column and side by side alignment, a print hammer engageable with said type head, means for moving said type head and said hammer simultaneously to successive printing positions, a plurality of keys each having an independent key lever, means operable for simultaneously shifting said type head laterally and angularly relative to said hammer in response to the depression of any one of said key levers so as to locate any one of said print characters in printing position, and means for actuating said hammer to strike said type head after the shifting of the latter has been completed.

2. A typewriter comprising, in combination, a prismatic type head having a plurality of print characters arranged on its faces in column by column and side by side align ment, a print hammer engageable with said type head, means for moving said type head and said hammer simultaneously to successive printing positions, means for yieldingly holding said type head in a home position with respect to said hammer at each printing position, a keyboard comprising a plurality of keys each having an independently operable key lever, means operable in response to depression of any one of said key levers for shifting said type head laterally and angularly relative to said hammer so as to locate any one of said print characters in printing position, and means for actuating said hammer to strike said type head after the shifting of the latter has been completed.

3. An improved typewriter construction comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, said type having a home position located centrally of said print characters, means moving said home position successively to stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print position, rotational selecting means for rotating said type head in prism face steps with respect to said print position, a plurality of independently operable key levers, means simultaneously actuating said lateral selecting means and said rotational selecting means in response to depression of any one of said key levers to present a selected character to a print position, a print hammer, and means actuating the same to strike said print position to effect the imprinting of one character at a time.

4. A typewriter comprising, in combination, a type head having a plurality of print characters arranged thereon, a print hammer engageable with said type head for effecting a printing of any one of said characters, means for moving said type head and said hammer simultaneously to successive printing positions, means for yieldingly holding said type head in a home position with respect to said hammer at each printing position, a keyboard comprising a plurality of independently operable key levers, means operablein response to depression of any one of said key levers for shifting said type head relative to said hammer so as to locate any one of said print characters in printing position, and means actuated in response to depression of said key lever for operating said hammer to strike said type head after the latter has been shifted.

5. An improved typewriter construction comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, said type head having a home position located centrally of said print characters, means moving said home position successively to stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print position, rotational selecting means for rotating said type head in prism face steps with respect to said print position, independently operable key lever means, means simultaneously actuating said lateral selecting means and said rotational selecting means in response to depression of any one of said key lever means to present a selected character to a print position, a print hammer, means actuating the same to strike said print position to effect the imprinting of one character at a time, and restoring means resetting said type head to its home position after each character imprinting.

6. An improved typewriter comprising a prismatic type head having a number of print characters arranged on its faces in column by column side by side alignment, said type head having a home position, means moving said home position successively to stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print position, rotational selecting means for rotating said type head in prism face steps with respect to said print position, means simultaneously actuating said lateral selecting means and said rotational selecting means to present a selected character to a print position, restoring means for resetting said type head to its home position after each character imprinting, a print hammer, and means actuating the same to strike said print position to effect the imprinting of one character at a time, said simultaneous actuating means comprising a plurality of laterally displaceable permutation bars with at least one of said bars being positioned to actuate each of said rotational and lateral selecting means respectively, a plurality of key bars positioned transversely of said permutation bars, and means laterally moving said permutation bars in response to depression of said key bars.

7. An improved typewriter comprising a prismatic type head having a number of print characters arranged in column by column and side by side alignment, a print hammer engageable with said type head, said type head having a home position, means moving said home position and said hammer simultaneously to successively stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print position, means for simultaneously actuating said lateral selecting means and said rotational selecting means to present a selected character to a print position, restoring means for resetting said type head to its home position after each character imprinting, said simultaneous actuating means comprising a plurality of laterally displaceable permutation bars with at least one of said bars being arranged to actuate each of said rotational and lateral selecting means respectively, a plurality of key bars positioned transversely of said permutation bars, means for laterally moving said permutation bars in response to depression of said key bars, means including a spring biasing said print hammer towards said type head, a bail positioned to be responsive to depression of said key bars, a print hammer tape system including a solenoid for tensioning said tape to cook said print hammer after each character imprinting, and hammer release means operable in response to movement of said bail actuating said spring to drive said hammer towards said type head.

8. An improved typewriter comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, a print hammer engageable with said type head to print one character at a time, means moving said type head successively to stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print hammer, rotational selecting means for rotating said type head in prism face steps with respect to said print hammer, means simultaneously actuating said lateral selecting means and said rotational selecting means to present a selected character in printing position, said simultaneous actuating means comprising a plurality of laterally displaceable permutation bars with at least one of said bars being arranged to actuate each of said rotational and lateral selecting means respectively, a plurality of key bars positioned transversely of said permutation bars, and means for laterally moving said permutation bars in response to depression of said key bars.

9. A typewriter comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, a print hammer engageable with said type head to print one character at a time, said type head having a home position, ratchet means moving said home position and said print hammer simultaneously to successively stepped print positions, lateral selection means for superimposing a movement on said type head laterally with respect to said print hammer, rotational selecting means for rotating said type head in face steps with respect to said print hammer, means simultaneously actuating said lateral selecting means and said rotational selecting means to present a selected character in printing position, restoring means for resetting said type head to its home position after each character imprinting, said simultaneous actuating means comprising a plurality of laterally displaceable permutation bars with at least one thereof being arranged to actuate each of said rotational and lateral selecting means respectively, a plurality of key bars positioned transversely of said permutation bars, means laterally moving said permutation bars in response to depression of said key bars, means including a spring biasing said print hammer normally towards said type head, a bail positioned for movement in response to depression of said key bars to actuate said ratchet means, a hammer tape system including a solenoid for 'tensioning said tape to latch said print hammer after each character imprinting, and hammet release means operable in response to movement of said bail to permit said spring to drive said hammer towards said type head, said hammer release means comprising a latch release element and a solenoid coil circuit opening switch element with both elements being positioned for actuation in response to movement of said bail.

10. A typewriter construction comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, a print hammer engageable with said type head to print one character at a time, ratchet means moving said type head and said print hammer simultaneously to suecessive stepped print positions across a page, from a left to a right hand margin, lateral selection means for superimposing a movement on said type head laterally with respect to said print hammer, rotational selecting means for rotating said type head in face steps with respect to said print hammer, a keyboard comprising a plurality of keys each having an independently operable key lever, means operable in response to the depression of any of said key levers for operating said lateral selection means and said rotational selecting means, and a resetting mechanism for returning said type head and print hammer to said left hand margin after the printing of a line, said resetting mechanism comprising a resetting tape and pulley system including an integral exposed handle and means interconnecting said resetting tape and pulley system with said ratchet means.

11. A typewriter construction comprising a prismatic type head having a number of print characters arranged on its faces in column by column and side by side alignment, a print hammer engageable with said type head to print one character at a time, ratchet means moving said type head and said print hammer simultaneously to stepped print positions, lateral selection means for superimposing a movement of said type head laterally with respect to said print hammer, rotational selecting means for rotating said type head in face steps with respect to said print hammer, a keyboard comprising a plurality of independently operable key levers, means operable in response to depression of any one of said key levers for actuating said lateral selection means and said rotational selecting means, an inking ribbon transfer system including a feed reel and a wind reel, and means including a one way clutch interconnecting said wind reel and said ratchet means for operation of said wind reel in response to movement in one direction of said means.

12. An improved typewriter construction comprising a type head having a number of print characters arranged thereon, said type head having a home position, means for moving said home position successively to stepped print positions, first selecting means for superimposing a move ment of said home position in one plane with respect to said print position, second selecting means operable for superimposing a movement of said home position in a different plane with respect to said print position, a plurality of independently operable key levers, means operable in response to depression of any one of said key levers for simultaneously operating said first and second selecting means, and means for imprinting the character located at said print position after the operation of said first and second selecting means.

References Cited in the file of this patent UNITED STATES PATENTS 606,743 Stallman July 5, 1898 1,229,202 Potts June 5, 1917 2,069,277 Sacerdote Feb. 2, 1937 2,099,262 HDoubler et al. Nov. 16, 1937 2,105,731 Graves et al. Jan, 18, 1938 FOREIGN PATENTS 111,801 Switzerland Sept. 16, 1925 

